English

Spacetime structure near generic horizons and soft hair

High Energy Physics - Theory 2020-02-05 v1 General Relativity and Quantum Cosmology

Abstract

We explore the spacetime structure near non-extremal horizons in any spacetime dimension greater than two and discover a wealth of novel results: 1. Different boundary conditions are specified by a functional of the dynamical variables, describing inequivalent interactions at the horizon with a thermal bath. 2. The near horizon algebra of a set of boundary conditions, labeled by a parameter ss, is given by the semi-direct sum of diffeomorphisms at the horizon with "spin-ss supertranslations". For s=1s=1 we obtain the first explicit near horizon realization of the Bondi-Metzner-Sachs algebra. 3. For another choice, we find a non-linear extension of the Heisenberg algebra, generalizing recent results in three spacetime dimensions. This algebra allows to recover the aforementioned (linear) ones as composites. 4. These examples allow to equip not only black holes, but also cosmological horizons with soft hair. We also discuss implications of soft hair for black hole thermodynamics and entropy.

Keywords

Cite

@article{arxiv.1908.09833,
  title  = {Spacetime structure near generic horizons and soft hair},
  author = {Daniel Grumiller and Alfredo Pérez and M. M. Sheikh-Jabbari and Ricardo Troncoso and Céline Zwikel},
  journal= {arXiv preprint arXiv:1908.09833},
  year   = {2020}
}

Comments

20 pages

R2 v1 2026-06-23T10:57:13.049Z